This application claims the priority of German Application No. 10 2005 055 075.4, filed Nov. 18, 2005, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a motor vehicle with a capacitor device for feeding electric energy and, in particular, for feeding an electric drive machine of the motor vehicle.
Such vehicles already exist in a variety of many different models. For example, double layer capacitors (also called supercaps or high power capacitors) are used as energy accumulators in so-called hybrid vehicles, in which the drive torque is supplied either via an internal combustion engine and/or via an electric machine. In order to be able to work safely on these vehicles in the specialized repair workshop, the double layer capacitor has to be discharged beforehand with a special discharge device, until an existing residual voltage permanently falls below the value of a low voltage protective limit. Such discharge devices are connected externally to the double layer capacitor. In so doing, the double layer capacitor is specifically short-circuited via a discharge resistor; and the released energy is converted into heat via the discharge resistor (see JP-A 2004-282823).
The present invention is based on the problem of providing a motor vehicle with a capacitor device, in which a safe discharge process of the capacitor device is improved.
The invention solves this problem by providing a motor vehicle with a capacitor device for storing electric energy, and in particular for feeding an electric drive machine of the motor vehicle, wherein a short-circuiting switch is arranged in parallel to the terminal posts of the capacitor device, whereby the capacitor device may be discharged by actuating the short-circuiting switch without the intermediary activity of a separate discharge resistor. Preferred further developments of the invention are described and claimed herein.
The invention provides a controllable short-circuiting switch, by which the capacitor device may be short-circuited and discharged without the intermediary activity of an additional discharge resistor. This is possible with the use of a short-circuit-proof capacitor device, which may be short-circuited via a controllable short-circuiting switch. The resulting thermal energy is dissipated and/or destroyed by way of the intrinsic mass of the capacitor device. In a preferred design, the capacitor device is disposed in the side door sill or in the cardan tunnel (tunnel-like body structure on the floor side of the vehicle, in which the cardan shaft runs) of the body of the vehicle, and is functionally connected to the automotive body sheet metal in a heat conductive manner for the purpose of dissipating the heat in the event of a short-circuit.
The controllable short-circuiting switch may be constructed as a crash sensor switch and/or as an electronic switch, which can be actuated via a controller.
A short-circuiting switch, which is designed as a crash sensor switch, is constructed, for example, as a mechanical switch, which is actuated directly by way of a deformation of the side door sill. As an alternative, the crash sensor switch may also be constructed as an electronic switch, which is actuated via a controller, which processes crash sensor signals, or is actuated directly by means of separate crash sensors. As an alternative or in addition, the short-circuiting switch may also be constructed as an electronic switch, which can be actuated by means of an operator. To this end, the electronic switch can be actuated by a controller as a function of the operator's commands—for example, by way of an external diagnostic device, which can also be connected to the electric system of the vehicle by way of a diagnostic interface for the purpose of service work. It is also contemplated to control the electronic switch specifically by an operator via an additional switching element in the interior of the vehicle.
The capacitor device is disposed preferably in a side door sill or in the cardan tunnel of the body of the vehicle. The capacitor device is connected advantageously in a heat conductive manner to the parts of the body of the vehicle, in particular to the parts of the side door sill, or preferably to the parts of the cardan tunnel, respectively.
In an especially preferred design, the capacitor device consists of a plurality of capacitor cells, whereby the capacitor cells are wired together in series and are configured in the shape of the narrowest possible arch inside the side door sill or inside the cardan tunnel such that the terminal posts, which are to be short-circuited, exhibit the smallest possible spacing in relation to each other. In this way, unnecessarily long line connections (which carry a high current loading in the event of a short-circuit) may be avoided.
In the event of an accident, but also in the event that maintenance work is to be done on the vehicle, the inventive device makes it possible to switch the capacitor device in the vehicle to neutral with respect to the high voltages of the capacitor device within a few seconds. Complicated and protracted discharging processes, which are necessary in the conventional external discharge devices via separate discharge resistors, are not necessary. Furthermore, safety is significantly increased because the discharge device is now located inside the vehicle (or rather inside an integrated capacitor module) and, even in the event of an accident, can be activated and/or short-circuited, so that the vehicle may be switched free of high voltage in seconds. Another advantage may be seen in the fact that separate cooling devices for dissipating the thermal energy in the event of a short-circuit are not necessary.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.